Transcript Genetic Probability

Genetic Probability
VANDERVEER
BIOLOGY
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Teachers
Students
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Learning Goals:



Students will have a basic understanding of genetic probability
Students will be able to distinguish between a dominant and
recessive gene
Students will be able to distinguish between a genotype and
phenotype
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Learning Objective:
 Students will be able to use knowledge gained in
this activity to answer genetic probability questions
with 75% accuracy
Students
Procedures:



Follow each instructional activity
Participate in each practice activity
Complete the assessment with 75% accuracy
Good day! My name
is Gregor Mendel
and I will be
assisting you as you
learn about genetic
probability.
Home
Introduction
Monohybrid Cross
Dihybrid Cross
Multiplication Rule
Assessment
Let’s get
started!
Introduction to Genetic Probability
On the following slides you
will find basic genetic
definitions you need to
know, or already know:
Genetic Probability Definitions
Allele: a form of a gene
2. Dominant: will be expressed in the organisms
appearance or physiology; usually represented by an
upper case letter
3. Recessive: will not be expressed in the organisms
appearance or physiology unless the individual has 2
copies of the recessive allele; usually represented by a
lower case letter
1.
Genetic Probability Definitions Continued
4.
5.
Genotype: the genetic composition of an organism
Phenotype: the observable characteristics of an organism
Gregor Mendel Video
Oh, that’s
me!
Section Review
1.
What is an allele?
a. A chromosome
b. A letter
c. A form of a gene
Genetic Probability Definitions
Allele: a form of a gene
2. Dominant: will be expressed in the organisms
appearance or physiology; usually represented by an
upper case letter
3. Recessive: will not be expressed in the organisms
appearance or physiology unless the individual has 2
copies of the recessive allele; usually represented by a
lower case letter
4. Genotype: the genetic composition of an organism
5. Phenotype: the observable characteristics of an organism
1.
Back to review
question 1
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Next question
Super!
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You can
do it!
2. If a gene is not expressed in the organisms
appearance it is:
a. Dominant
b. Recessive
c. An allele
Genetic Probability Definitions
Allele: a form of a gene
2. Dominant: will be expressed in the organisms
appearance or physiology; usually represented by an
upper case letter
3. Recessive: will not be expressed in the organisms
appearance or physiology unless the individual has 2
copies of the recessive allele; usually represented by a
lower case letter
4. Genotype: the genetic composition of an organism
5. Phenotype: the observable characteristics of an organism
1.
Back to review
question 2
You’re right! 
Next question
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It’s okay,
try again!
3. The genetic composition of an organism is its
____________ and the observable characteristics
of an organism is its ____________.
a. Phenotype; genotype
b. Genotype; phenotype
c. Genotype; genotype
Genetic Probability Definitions
Allele: a form of a gene
2. Dominant: will be expressed in the organisms
appearance or physiology; usually represented by an
upper case letter
3. Recessive: will not be expressed in the organisms
appearance or physiology unless the individual has 2
copies of the recessive allele; usually represented by a
lower case letter
4. Genotype: the genetic composition of an organism
5. Phenotype: the observable characteristics of an organism
1.
Back to review
question 3
You’re right! 
Up Next:
Monohybrid Cross
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Think!
Monohybrid Cross
 A monohybrid cross is a cross involving a single trait
with two alleles.
 In example, X is the trait and X, x are the alleles.
X
X
x
Xx
Xx
x
Xx
Xx
Monohybrid Cross Using a Punnett Square
Seed color: Y=yellow
y= green
Cross: Yy x YY
Y
y
Y
YY
Yy
Y
YY
Yy
Y
y
Y
YY
Yy
Y
YY
Yy
What is the genotypic ratio? 2 YY: 2 Yy or 1 YY: 1Yy
What is the phenotypic ratio? All yellow
Monohybrid Cross Using a Punnett Square: Practice
Eye color: B=brown
b= blue
Cross: Bb x Bb
B
b
B
BB
Bb
b
Bb
bb
Check your work:
B
b
B
BB
Bb
b
Bb
bb
 What is the genotypic ratio? 1 BB: 2 Bb: 1 bb
 What is the phenotypic ratio? 3 brown: 1 blue
Dihybrid cross
 A dihybrid cross is a cross involving 2 traits with two
alleles each.
 In example, X and Y are the traits and X, x/ Y, y are
the alleles.
XY
XY
XY
XY
xy
XxYy
XxYy
XxYy
XxYy
xy
XxYy
XxYy
XxYy
XxYy
xy
XxYy
XxYy
XxYy
XxYy
xy
XxYy
XxYy
XxYy
XxYy
Dihybrid Cross Using a Punnett Square
Seed color: Y=yellow
y= green
W= Wrinkled
w=round
Cross: YyWw x Yyww
YW
Yw
yW
yw
Yw
YYWw
YYww
YyWw
Yyww
Yw
YYWw
YYww
YyWw
Yyww
yw
YyWw
Yyww
yyWw
yyww
yw
YyWw
Yyww
yyWw
yyww
YW
Yw
yW
yw
Yw
YYWw
YYww
YyWw
Yyww
Yw
YYWw
YYww
YyWw
Yyww
yw
YyWw
Yyww
yyWw
yyww
yw
YyWw
Yyww
yyWw
yyww
 What is the genotypic ratio?
2 YYWw: 2 YYww: 4 YyWw: 4 Yyww: 2 yyWw: 2 yyww
reduced to 1 YYWw: 1 YYww: 2 YyWw: 2 Yyww: 1 yyWw: 1 yyww
 What is the phenotypic ratio?
6 Yellow wrinkled: 6 Yellow round: 2 green wrinkled: 2 green round
Reduced to 3 yellow wrinkled: 3 yellow round: 1 green wrinkled: 1 green
round
Dihybrid Cross Using a Punnett Square: Practice
Seed color: B=Brown
b= blue
G= brunette
g= blonde
Cross: BBGg x bbgg
BG
Bg
BG
Bg
bg
BbGg
Bbgg
BbGg
Bbgg
bg
BbGg
Bbgg
BbGg
Bbgg
bg
BbGg
Bbgg
BbGg
Bbgg
bg
BbGg
Bbgg
BbGg
Bbgg
Check Your Work:
BG
Bg
BG
Bg
bg
BbGg
Bbgg
BbGg
Bbgg
bg
BbGg
Bbgg
BbGg
Bbgg
bg
BbGg
Bbgg
BbGg
Bbgg
bg
BbGg
Bbgg
BbGg
Bbgg
 What is the genotypic ratio?
 What is the phenotypic ratio?
Check Your Work:
 What is the genotypic ratio?
8 BbGg: 8 Bbgg
Reduced to 1 BbGg: 1 Bbgg
 What is the phenotypic ratio?
8 Brown/brown: 8 Brown/ blonde
Reduced to 1 Brown/brown: 1 Brown/blonde
Multiplication Rule
If two events are independent, then the joint
probability is:
P(A and B)= P(A) x P(B)
Dihybrid Cross using Multiplication Rule
Seed color: Y=yellow
y= green
W= Wrinkled
w=round
Cross: YyWw x YyWw
What is the probability of getting the genotype YyWw?
(2/4) (2/4)= 4/16= ¼
What is the probability of getting the genotype YYww?
(1/4)(1/4)= 1/16
Dihybrid Cross using Multiplication Rule: Practice
Seed color: B=Brown
b= blue
G= brunette
g= blonde
Cross: bbGg x bbGG
What is the probability of getting the genotype bbGg?
What is the probability of getting the genotype bbGG?
Check Your Work:
What is the probability of getting the genotype bbGg?
(1)(1/2)= ½
What is the probability of getting the genotype bbGG?
(1)(1/2)= ½
Assessment
You must answer ¾ of the following questions
correctly to complete this activity.
This will be a
piece of cake
now that we’ve
completed the
activities!
Question 1
An allele is:
a. A form of a gene
b. Gregor Mendel’s nickname
c. A chromosome
You’re right! 
Next Question
Perfect!
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You can
do it!
Question 2
Solve using a Punnett Square. What is the phenotypic
ratio of the following cross?
Bb x BB
a. 1:1
b. 2:2
c. All are the same
You’re right! 
Next Question
Here,
here!
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Try Again!
Ponder this
one some
more
Question 3
Solve using a Punnett Square. What is the genotypic
ratio of this cross?
YyWw x YyWw
a. 1:1:2:2:1:1
b. 9:3:3:1
c. 12:3:1
You’re right! 
Next Question
Good
work!
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Try Again!
You’ve
got this!
Question 4
Solve using the Multiplication Rule. What is the
genotypic ratio of the following cross?
Yyww x yyww
a. 1:1
b. 2:2
c. 9:3:3:1
You’re right! 
Final Slide
Good job!
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Think!
Almost there ...
 If you have …
 Followed each instructional activity
 Participated in each practice activity
 Completed the assessment with 75% accuracy
 Then you’re done!
Congratulations!